DiCarlo has a long and well-argued post on how and why Firefox’s attempts to ape Google Chrome have not only made the browser less usable, but done the very thing Mozilla was trying to prevent — driving people to switch to Chrome.

The problem, argues DiCarlo, isn’t just the rapid releases, but the way Mozilla has handled them:

Ironically, by doing rapid releases poorly, we just made Firefox look like an inferior version of Chrome. And by pushing a never-ending stream of updates on people who didn’t want them, we drove a lot of those people to Chrome; exactly what we were trying to prevent.

That squares with the user feedback Webmonkey has received over the last year or so of rapid Firefox updates — comment after comment of fed-up users tired of the endless updates and dialog boxes. Less anecdotally, Webmonkey traffic from Firefox has declined from roughly 34 percent to roughly 30 percent since Firefox 4 and the rapid release cycle debuted.

The problem isn’t the updates necessarily — security updates, bug fixes and support for new web standards are all necessary, even welcome, things — it’s the way that Mozilla has handled them, using intrusive dialogs that interrupt work and cause frustration, that sends users to other browsers.

Of course bug fixes, security updates and standards support aren’t the only things Firefox has been packing into the rapid release cycles. DiCarlo also calls out Mozilla’s user interface designers, arguing that using the rapid release cycle to constantly change Firefox’s interface compounds the problem and user frustration.

After years of aspiring to improve software usability, I’ve come to the extremely humbling realization that the single best thing most companies could do to improve usability is to stop changing the UI so often! Let it remain stable long enough for us to learn it and get good at it. There’s no UI better than one you already know, and no UI worse than one you thought you knew but now have to relearn.

DiCarlo’s post has understandably provoked some heated discussion, both on his site and in a Hacker News thread (DiCarlo’s site has also been up and down today, the Google cache version is here if the original is not currently working). Mozilla is in the process of addressing some of these problems, and plans to make the update process less intrusive in future release, but for many users the damage has already been done.